Consider a conical pendulum that consists of a bob on one end of a string of negligible mass with the other end of the string attached to a point on the ceiling, as shown below. Given the proper push, this pendulum can swing in a circle at a given angle, maintaining the same distance from the ceiling throughout its swing. If the mass of the bob is m, the length of the string is d, and the angle at which it swings is theta, what is the speed v of the mass as it swings? Hint: Find the vertical and inward radial components of the string's tension.